1. Field of the Invention
The present invention relates to a car top carrier, and particularly one that is automatically adjustable to apply a predetermined level of contractive force for mounting on any car top. The preferred embodiment of the support includes a torque limiting device in combination with the crankshaft means, so that only a pre-determined contractive force may be exerted by the carrier, upon the car top. The present invention may be used as a mounting for any form of car top carrier, including a superposed container adapted for additional carrying space. The present support is further useful as an auxillary carrying rack, for supporting any number of articles necessarily carried external to a vehicle.
2. Description of the Prior Art
Numerous car top constructions are known in the prior art, but none which allow for an automatic pre-selection of the contractive forces exerted by the engaging means onto the car top. Additionally, there is not found a car top carrier support characterized by support tubes telescoping within a carrier track, wherein the car top engaging means are fixed upon vertical support legs located proximate the outer ends of each tube. Representative of the prior art are the following U.S. Pat. Nos.: BINDING, 3,899,111; READ, 3,897,895; CARSON, 3,877,624; OLIVEIRA, 3,495,750; OLSON, 2,888,178; BARRECA, 2,833,453; GALLAGHER, 2,788,929; STRAUSS, 2,222,636.
The patent to Binding illustrates a car top carrier which is usable with a gutterless car top, and includes a spring mounted clamping linkage having a hook to engage a ledge on either side of the gutterless car top. As such, the patent to Binding shows a car top carrier tensioned upon an automobile roof, but without provision for automatically controlling the amount of tension between the carrier and the vehicle roof, or locating the support legs at the roof edge.
The patent to Read illustrates a car top carrier wherein tensioning of the carrier on the roof is accomplished by separately engaging a jamming mechanism. Read does not illustrate automatic positioning of the feet of the carrier proximate the strongest part of the vehicle roof, and further does not provide for an automatic limiting of applied tension. The patent to Carson illustrates a conventionally mounted car top carrier, with a clamping assembly for holding various objects onto the rack. As such, Carson does not provide for telescoping support tubes for tensioning with respect to the vehicle roof. The patent to Oliveira illustrates a collapsible luggage rack wherein the support feet are manually positioned on the vehicle roof. The amount of tension exerted by the mounting pads on the roof is controlled by the tension of a separate spring, passing through the interior of the main support. Oliveira teaches another collapsible luggage rack that is without provision for supplying a pre-selected mounting force through a telescoping, car top edge engaging means.
The patent to Olson employs a support bar of constant length, with only the tension of the roof mounting hooks controllable through the provision of a wind-up reel, together with a pawl. Olson has no provision for maintaining the support feet adjacent the edges of the vehicle roof and, additionally, there is no provision for automatically controlling the maximum tension between the rack and the vehicle roof.
The patent to Barreca illustrates a form of constant length support bar wherein the relative tensioning between the rack and the roof is simply adjusted by a crank assembly. Barreca's device does not provide for a support mechanism of varying lengths so that the support feet are maintained adjacent the edge of the vehicle roof, with the additional provision of an automatic tensioning means to absolutely limit the maximum tension which may be applied upon the vehicle roof itself.
The patent to Gallagher employs a constant length support bar which is conventionally attached to a vehicle roof, through straps. Gallagher includes a cranking means for engaging a load superposed upon the support, but is without provision for automatically tensioning the car top carrier onto the roof itself. Finally the patent to Strauss illustrates a turnbuckle arrangement for tensioning a roof mounted accessory onto a vehicle roof. Straus does not provide a pair of telescoping support tubes within one continuous load support, nor does he have the additional feature of automatic means to limit contractive forces exerted upon the vehicle roof.